How do I change right click to left click when in timeline mode?
Found this online and it worked for me:

The Timeline scrubbing is under: File > User Preferences... > Input > Animation >Change Frame (Timeline Scrubbing).

The "Change Frame" default was set to "Action Mouse"(I still have no idea what action mouse button is).

I changed that to "Left Mouse."

However since Left Mouse in Timeline was already used for interacting with the "Time Marker" in Timeline, I had to change that input to something else(I changed it to Middle Mouse).